"Sumer is icumen in" is the incipit of a medieval English round or of the mid-13th century; it is also known variously as the Summer Canon and the Cuckoo Song.

The history of Sumer spans through the 5th to 3rd millennia BCE in southern Mesopotamia, and is taken to include the prehistoric Ubaid and Uruk periods.

Warfare in Sumer predominantly consisted of small-scale conflicts between nearby city-states.

(Sumerian: lugal-ki-en-gi-ki-uri, Akkadian: šar māt Šumeri u Akkadi) a royal title in Ancient Mesopotamia combining the titles of "King of Akkad", the ruling title held by the monarchs of the Akkadian Empire with the title of "King of Sumer".

“Mirie it is while sumer ilast” (“Merry it is while summer ylast”) is a Middle English song from the first half of the 13th century.